1. Field of the Invention
The invention relates generally to an apparatus and method for selectively applying grouting material directly to a targeted location.
2. Description of Related Art
Grout is widely used to fill the gaps and seal the joints between floor and wall tiles, etc. Grout is known to come in a wide variety of types and colors to fit the specific requirements of the grouting job to be performed. Grout is typically prepared at or near the time and location of the project to be performed. Generally enough grout is prepared to complete the grouting of an entire target surface or group of surfaces. Applying grout from the same batch assures that the appearance of the grout on such target surface or surfaces will appear uniform. Grout is typically applied by spreading a grout material on the surface of a tiled surface and working the grout into the joints. After the filling of the joints are complete, the excess grout is scrapped off the tile. Next, the tiles are wiped off using a damp sponge, cloth or other suitable item. In performing such cleaning, operators must be careful not to remove the grout that has been worked into the joints; otherwise the operator must repeat the grouting steps to repair the damage to the previously grouted joint.
Applicators have been developed to reduce the time needed to apply grout to a tiled area. Such applicators attempt to reduce clean up time by attempting to apply the grout directly to the joint itself while avoiding contact with the tile surfaces. For example, an applicator has been developed which uses plunger for forcing grout out of a nozzle under pressure into the gap between tiles to ensure a proper amount of grout is within the gap. This device includes a tube assembly having a piston passageway with a smooth cylinder bore wall and a threaded tip end and an open handle end with a detachable u-shaped hand grip assembly removably attached to the outside. Further, the tube assembly has a separate injector tube, nose piece and nozzle tip. Grout is forced out of the tube from the nozzle end, where, an operator, using two hands, grabs the u-shaped handle with one hand, and with the other hand, grabs the plunger handle and pushes on the plunger handle while pulling on the u-shaped handle end. The u-shaped hand grip assembly is removably attached to the outside of the tube assembly via a hose-type clamp. The hose-type clam has a screw and worm drive where the u-shape handle is slid over the tube assembly and the worm screw is tightened until the corresponding circular band is tightened sufficiently about the tube assembly such that it will remain static during the push-pull operation of the applicator. To remove the unshaped handle, the same worm screw is loosened until the circular band is sufficiently loose to slide off the tube assembly.
Although such device provides the advantage of providing a tool that allows for the directed and controlled release of grout to a desired gap between tiles, many drawbacks still remain. One area of concern is the difficulty in using this design. Here, an operator must use two hands to create the pressure for extruding the grout from the device. Further, the push-pull design of the device requires that an operator position themselves behind the length of the device at the end of the plunger handle, thus creating a corresponding distance between the operator's eye, and the gap being filled. Further, each operator must go through a learning process as to how to operate such a unique mechanism.
Another area of concern is the time and effort needed to replace an empty tube. If an operator has assembled a series of pre-filled tube assemblies and wishes to sequentially switch from each used up tube assembly to a waiting pre-filled assembly, the operator must take the time and effort to set-aside the device, retrieve a separate tool (a screwdriver) to assist in removing the u-shaped handle, use the tool to loosen the u-shaped handle from the tube assembly, remove the handle from the tube, slide the handle around the new filled tube assembly, use the screwdriver to tighten the u-shaped handle about the tube, and reposition themselves behind the device to continue the grouting process.
Another area of concern is the cost of the tube assembly itself. The cost of an assembly tube includes the following: the material cost to provide sufficient structural integrity such that the tightening of the u-shaped device thereabout does not cause such a constriction which impedes the stroke of the plunger through the chamber located inside, the material cost to provide sufficient applicator tube integrity such that the push-pull motion about the device does not deform the applicator tube and otherwise negatively impede the use of the device, the material cost to include a platform-type component at the plunger end of the tube for providing structural support for the opening of the tube, and the manufacture and material costs associated with the production and design of a applicator tube having separate sections. In addition, this design includes an angled nose piece that does not provide for the extrusion of the grout therein resulting in the loss of such grout if discarded, or requires the time and energy to retrieve the remaining grout. Further, all the above costs are multiplied when it is desired to use multiple applicator tubes to complete a grouting operation.
Another area of concern is the reliability of the device. Because the tube is constructed of multiple parts, and the operation of the piston crosses a seam of such multiple parts, there is inherent reliability issues and wear-and-tear issues regarding the repeated crossing of such boundary by the internal plunger. Further, the lack of a centering mechanism for the shaft leading to the plunger, and the general instability of the overall push-pull design, each contribute to a torquing of the shaft and a resulting torquing of the plunger. Such torquing of the plunger raises issue of jeopardizing the seal upon such movements as well as the longer term wear-and-tear on the inner walls of the assembly tube and the plunger.
Other application devices, although not generally known to be used in conjunction with grouting operations, but generally known to be used with caulking operations, are caulking guns. Such caulking guns are hand-held devices using a griping-trigger assembly to control the movement of piston-plate mechanism to cause the extrusion of caulking material stored in an interchangeable caulking tube. Here, the caulking gun is a tool used to act upon a disposable caulking tube. Pre-filled caulking tubes are purchased for use and discarded after the pre-filled caulking material has been dispensed. The limited types and colors of caulks used allows manufacturers to easily and economically produce and sell such pre-filled caulking tubes. The caulking tube designs are typified by their use of a cardboard or plastic tube to form its outer/inner shell. At one end of the tube is an applicator tip. At the other end is an opening that exposes the full width of the inner shell. Inside the inner shell, although obscured by a push-plate, is the caulking material. The push-plate is a circular plate with a perpendicular boarder around its edge where the perpendicular boarder or sides extend down towards the open end of the tube. The push-plate is used to urge the caulking material down the inner shaft and out the applicator tip. The push-plate also provides an atmospheric seal between the caulking material and the empty portion of the inner shaft, allowing the caulking material inside to be stored for an indefinite time before its use.
Force is applied against the push-plate by a piston-plate mechanism, which forces the caulking material out of the application tip. The piston-plate mechanism is characterized by a shaft extending down the inner shaft of the caulking tube with a plate that contacts and pushes the push-plate. The push-plate provides the necessary wall-to-wall coverage to displace the caulk material down the inner shaft. It is not necessary that the piston-plate plate extend to the wall surfaces. The push-plate has its perpendicular sides extending down the open end of the tube. The piston-plate's plate is in contact with the surface of push-plate's circular plate beyond the edges of such perpendicular sides. The width of the piston-plate plate cannot extend from wall-to-wall, as the sides of the push-plate, having a certain thickness, are located there between. As such, any piston-plate plate must be smaller in diameter than the diameter of the inner tube and no greater than the diameter between the two perpendicular sides of the push-plate. In fact, the reason for the use of the push plate generally, is as a footing to prevent the piston-plate's piston from breaching, or breaking through, the push-plate barrier and contacting the caulking material itself.
One of the preferred caulking gun design includes the use of a gasket that is of a diameter larger than the diameter of the inner tube and which extends about the edges of the piston-plate plate. Further, this circular gasket is held in place by the use of two piston-plates sandwiched on either side of such gasket. The gasket is designed to extend from the edges of the piston-plate plates and extend partially along the perpendicular sides of the push-plate, so as not to exceed the ends of such perpendicular sides. This design provides a vacuum between the piston-plates and the push-plate such that a moving back of the piston-plate pulls the push-plate, via a vacuum therebetween, in a backward motion. Therefore, this design requires that the gasket does not extend to the walls of the tube, as this would interfere with both the vacuum attempted to be created between the two plates, and with the backward movement of the push-plate along the walls of the tube.
Another preferred caulking gun design does not alter the diameter of the plunger-plate, but adds a spring-like mechanism used in the retraction of the associated piston rod. Here again, this design uses a plunger plate that fits within the diameter of the perpendicular sides of the push-plate and does not use a gasket. This caulking gun design is concerned with retaining the caulking tube or cartridge within the caulking gun until it is intentionally released by the operator. One embodiment here introduces a spring-like plate behind the plunger plate that resists movement in the backward direction, when the plunger-plate is approaching the exit point of the caulking tube.
Yet another design proposes a interchangeable plunger-plate design where the caulking gun accepts either of two sized cartridges, namely a ¼ gallon or {fraction (1/10)} gallon cartridge. Here, depending on the size of the caulking cartridge, either a smaller or larger plunger-plate is used. In both cases, the plunger-plates are standard size for their corresponding caulking cartridges. As such, they are designed to fit between the perpendicular walls of the corresponding push-plates, and do not contain a flexible gasket.
As demonstrated above, a need exists for a refillable, hand-squeezed driven grouting applicator. Desirably, the new apparatus is capable of dispensing grouting material without the use of a push-plate. Further it would be desirable if the new apparatus was capable of extruding the grout without the need for an operator to use two hands.